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Joe Ogiba
Post Laureate
Reged: 02/14/02
Posts: 3361
Loc: NJ USA
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Quote:
Hi Bob,
FYI, the Kowa TSN-661 is waterproof and to a higher standard than the Fujinon and Pentax binos too. You should also say that at ~1000g it is a good 2x lighter/smaller than the Fujinon too.
I have just started playing around with spotting scopes myself. I have both the Kowa TSN-663 Prominar and a Pentax PF-65ED. The Pentax can accept standard 1.25" astronomical eyepieces. But what I think makes a spotting scope really cool is their ability to take a cheap $100 digicam and transform into a fairly fast F2.5-F5.5 800mm-2500mm terrestrial telephoto lens. An equivalent DSLR zoom lens if even made in these focal lengths would cost $10,000's more and be 20x heavier!
clear skies,
Rick
You are not getting F5.5 @2,500mm , you would need an 18" aperture.
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Pentax PF-80ED
Meade 102ED APO
Orion EON 72
120ST
Apex 127
C6 XLT
CR150
C9.25
XT10
Zeiss 7x42 FL
Canon 10x42L IS WP
15x50 IS
12x36 IS II
Garrett Optical 28x110 HD-WP Signature Series
Oberwerk BT-80 45
Apogee RA-88-SA
Denk II Power x Switch binoviewer w/13mm Ethos, 20mm Pentax XW's, 20mm Widescan III's.
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Rick
Carpal Tunnel
Reged: 04/12/05
Posts: 2574
Loc: Tokyo, Japan
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On the contrary Joe, this is what makes digiscoping so darn cool! Check this out!
Or this!
The focal lengths I mentioned are 35mm lens equivalents. It is also why using a small digicam is preferable to using a DSLR where you are limited to F12-13. At these slower speeds, a big heavy mount is needed and the image can still be affected by "mirro slap" when the shutter is released. Using a "fast" digicam lets you get by with small, lighter weight mounts.
clear skies,
Rick
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www.japanastro.com
Edited by Rick (05/10/08 09:54 PM)
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Joe Ogiba
Post Laureate
Reged: 02/14/02
Posts: 3361
Loc: NJ USA
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So if I use my 50mm F1.4 lens on my Pentax DSLR with adapter ring to fit on an eyepiece on my 2350mm F10 C9.25 it should change the C9.25 into a F1.4 lens. 
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Pentax PF-80ED
Meade 102ED APO
Orion EON 72
120ST
Apex 127
C6 XLT
CR150
C9.25
XT10
Zeiss 7x42 FL
Canon 10x42L IS WP
15x50 IS
12x36 IS II
Garrett Optical 28x110 HD-WP Signature Series
Oberwerk BT-80 45
Apogee RA-88-SA
Denk II Power x Switch binoviewer w/13mm Ethos, 20mm Pentax XW's, 20mm Widescan III's.
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Luigi
Carpal Tunnel
Reged: 07/03/07
Posts: 2054
Loc: Massachusetts
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Tony, Kenny J, and others have it right. One thing I would add to get a good set of bins that are small and light enough so that you usually have them with you. Something in the range of 8x32 or 8x42. Larger bins, though better for astro, don't often get taken along. Only get a spotting scope if you need a rugged waterproof scope. Various eyepieces are generally available for the better spotters though the most commonly used are zoom EPs. These can be pretty good but they sacrifice FOV and edge sharpness compared to fixed fl EPs. Astro scopes are much more versatile.
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17.5" f/5 Discovery Truss
IM715 7" f/15 MCT, Eon-120ED
Lunt 60mm single etalon HA
CG5A coffee grinder, Orion Skyview Alt-AZ
35,19,15 Pans.9 Nag. Meade 24.5 4kSWA, 4.7 5kUWA.
BO-TMB 7mm planetary.
Zeiss Diascope 85
Zeiss, Leica, Canon IS, Fujinon, Nikon binos
One each generic rescue Greyhound (pictured)
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Wes James
Carpal Tunnel
Reged: 04/12/06
Posts: 2457
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I have started reading this thread with interest, as I have zero knowledge or familiarity with spotting scopes. I have a SV 80mm NHNG scope... how would that compare with the current range of spotting scopes?
Edit: I do realize there's the issue of correct/upright image which would have to be dealt with in the diagonal.
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Wes
Atlantic Beach, FL
Some bino’s from Miyauchi 5x32 Binon's up through Garrett 20x110 Signature's,
Some telescopes from a Stellarvue 80mm NHNG up through a couple of 8” reflectors…
And a wonderful 4.25" Delmarva Shiefspiegler!
Some good friends, made here on C/N.
Oh- several cats and a wonderful wife!
Anyone want a cat???? :-O
"When your work speaks for itself- Don't Interrupt" -Gamble Rogers
Edited by Wes James (05/11/08 12:59 PM)
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Rick
Carpal Tunnel
Reged: 04/12/05
Posts: 2574
Loc: Tokyo, Japan
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Hi Wes,
Astro scopes are generally optically superior to fieldscopes mainly because of the fieldscopes built-in RACI prism. The TV-76/85, C5, Questars, and MC90/127 are tops in this class. They take much higher powers than the dedicated fieldscope's 60x-75x but how useful that is depends on the atmospheric condition. Common useful fieldscope mags are 20x, 30x, 45x, and 60x. 30x is probably the most common visually and 20x is best for digiscoping.
Dedicated fieldscopes are usually smaller and much lighter than astro scopes, typically 500g-1500g for 50mm-85mm sizes. Only the BORGs can compete with this spec. With the exception of the Pentax line, fieldscopes all use proprietary eyepiece designs.
Digiscoping with a digicam and fieldscope was "invented" by a now deceased Malaysian birder and is a relatively new development that now has the full embrace of the various fieldscope OEMs. Probably the biggest boon for the birding hobby in decades.
hope this helps,
Rick
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www.japanastro.com
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Wes James
Carpal Tunnel
Reged: 04/12/06
Posts: 2457
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Rick-
Thanks so much for the addtional insight... you covered many obscure differences in a very brief way- thanks for the information!
Wes
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